1. Field of the Invention
The present invention relates to a video recording apparatus and a reproducing apparatus which are suitable for use in a television receiver in which a program is always recorded to a recording medium and, more particularly, to a setting of a long time recording mode and a retrieval of a desired scene or program from recorded picture planes.
2. Description of the Related Art
It often happens that a telephone suddenly rings or a visitor suddenly comes while the user is enjoying a television broadcasting and he misses a broadcasting program. When a television broadcasting program is missed, except for a program which will be broadcasted again, the user can never watch again such a program. A program which will be broadcasted again in a short period is unusual. In most cases, news programs and sports programs are not broadcasted again. In many cases, therefore, when a television broadcasting program is missed, the program cannot be watched again.
There is also a case where a scene which is desired to be stored suddenly starts while a broadcasting program such as excellent scene of a movie or drama, interview with an important person, a highlight scene of a sports program, or the like is watched. In such a case, even if a VTR is immediately set, it often happens that the VTR cannot be ready to record such a scene and the scene cannot be recorded.
The inventors of the invention, therefore, have proposed a television receiver such that while the broadcasting program is watched, the program is always recorded to a recording medium. According to such a television receiver, even if a telephone suddenly rings or a visitor suddenly comes, the user can go back and reproduce the program, so that the program is not missed. Since the program can be easily stored, even if a program which is desired to be recorded suddenly starts, the television receiver can cope with such a situation.
The inventors of the invention have also proposed the use of a hard disk drive as a recording medium in the television receiver which always records a program to the recording medium as mentioned above. Hitherto, as a recording medium for recording a video signal, a magnetic tape is widely used. However, an accessing speed of the magnetic tape is slow and it is difficult to employ the magnetic tape as a recording medium which is used in the television receiver. Although the use of a semiconductor memory is considered, the semiconductor memory of a large capacity is very expensive and is not suitable for a case where a program is stored for a long time since the stored program is erased when the power source is turned off. On the contrary, the hard disk drive has a large capacity and a sufficiently high accessing speed.
When the video signal is recorded to the hard disk drive as mentioned above, it is further desirable that the long time recording can be performed in accordance with an application. In case of recording the video signal to a tape, by changing a feeding speed of the tape, the long time recording can be realized. For example, the long time recording mode is called a triple time mode in the VHS system and is called an LP mode in an 8 mm VTR. In those modes, by changing the feeding speed of the tape, the long time recording mode is set.
In case of recording the video signal to the hard disk drive as well, it is desired that the long time recording mode can be set in a manner similar to the triple time mode of the VHS system and the LP mode of the 8 mm VTR.
When the video signal is recorded into the hard disk drive, however, the long time mode cannot be realized by a method similar to that in the case where the video signal is recorded to the tape.
In the conventional VTR, since the long time recording mode is set by changing the feeding speed of the tape, there is a problem such that a reproduction picture plane is disturbed by a switching of the recording mode.
It is, therefore, an object of the invention to provide a video recording apparatus and a reproducing apparatus which can easily set a long time recording mode when a video signal is recorded to a recording medium such as a hard disk or the like.
When the recording time of a program is long, it is difficult for the user to search a desired scene. For example, when the video signal is compressed by the motion JPEG and recorded by using a hard disk drive of a capacity of about 1 Gbytes, a recording time of about 60 minutes can be assured. It is, however, not easy to search a desired scene from recording picture planes of the long time and reproduce it.
A method of preliminarily recording images distinguished as index images and searching by reading out the index images in accordance with a predetermined procedure, a method of detecting a scene change and searching by using the detected image at the time of the scene change as an index image, a method of simply dividing a recording time every predetermined time and using a representative image of each time zone as an index, and the like are considered.
According to the method of preliminarily recording the images distinguished as index images and searching by reading out the index images by the determined procedure, it is necessary to record the determined index images. The method cannot be applied to a case of searching the contents of the recorded received picture plane. According to the method of detecting the scene change in the reproduction picture plane and using the position where the scene is changed as an index, a correlation detecting circuit or a motion detecting circuit for detecting the scene change is necessary, so that a circuit scale is increased and the costs are increased. In the method of simply dividing the recording time every predetermined time and using a representative image of each time zone as an index, since the image is not always a significant image in which the position of the search image can be identified, an efficient search cannot be performed.
As mentioned above, when the received picture plane is recorded to the hard disk drive, since the video data has been compressed and recorded, it is difficult to form index images by simply dividing the recording time every predetermined time.
That is, when the received picture plane is recorded to the hard disk drive apparatus as mentioned above, video data is compressed in order to improve the recording time. As a video data compression processing method, an MPEG (Motion Picture Experts Group) system and a motion JPEG (Joint Photographics Coding Experts Group) system are known. Although a compression efficiency of the MPEG system is high, since the compression in the time base direction is performed, it is difficult to search or reproduce the data at variable speeds on a field unit basis. When the received picture plane is recorded in the hard disk, it can be considered to compress the video data by the motion JPEG system.
In the motion JPEG system, however, a compression ratio of the picture plane is different in dependence on a pattern or the like. Consequently, when the video data is compressed by the motion JPEG and is recorded into the hard disk drive, a correspondence between the address in the hard disk drive and a recording time cannot be obtained. The recording time cannot be, therefore, simply obtained from the addresses of the hard disk drive and it is difficult to divide the recording time every predetermined time and display.
It is, therefore, another object of the invention to provide a video recording apparatus, a video reproducing apparatus, and a recording and reproducing method of the apparatuses, in which a desired scene or program can be easily searched from recorded picture planes without causing an increase in circuit scale and costs.
According to the invention, there is provided a video apparatus comprising: a recording medium on which moving image information is recorded; time-divisional means for dividing the moving image information recorded on the recording medium every predetermined time; display means for displaying the moving image information; picture plane division display means for dividing a picture plane area of the display means into a plurality of small picture plane areas and displaying the moving image information of every predetermined time divided by the time-divisional means as an index image in correspondence to each of the plurality of divided small picture plane areas; and input means for designating a desired one of the index images which are displayed in the plurality of small picture plane areas, wherein when the index image is designated by the input means, the moving image information corresponding to the designated index image is read out from the recording medium and is displayed by the display means.
According to the invention, the video apparatus further comprises offset means for giving an offset time of a predetermined amount to the moving image information of every predetermined time divided by the time-divisional means.
According to the invention, there is provided a display method of a video apparatus, comprising the steps of: dividing moving image information recorded on a recording medium every predetermined time; dividing a picture plane area to display the moving image information into a plurality of small picture plane areas and displaying the moving image information divided every predetermined times as an index image in correspondence to each of the plurality of divided small picture plane areas; designating a desired one of the index images which are displayed in the plurality of small picture plane areas; and when the index image is designated, reading out the moving image information corresponding to the designated index image from the recording medium and displaying.
According to the invention, the display method further includes a step of giving an offset time of a predetermined amount to the moving image information of every predetermined time.
When an overview search key is depressed, the display picture plane is divided into a plurality of small picture planes and an image of video data of every predetermined time recorded in a hard disk drive is divisionally displayed in each divided picture plane. When the overview search key is further pressed, the time of each picture plane is offset every predetermined time. Therefore, a desired reproduction start position can be easily retrieved from the index picture planes.
According to the invention, there is provided a video apparatus comprising: video compressing means which compresses a video signal of a predetermined unit so as to have a fixed length and whose compression ratio can be changed; input means to which mode set inputs to set a standard recording mode and a long time recording mode are given; compression ratio setting means for varying the compression ratio of the video compressing means in accordance with a mode set inputs from the input means; and recording means for forming blocks obtained by adding status information including information of the recording mode to the compressed video signal and recording the video signal and the status information onto a recording medium on a block unit basis.
According to the invention, there is provided a video apparatus for reproducing a video signal and status information from a recording medium on a unit basis of a block obtained by adding the status information including information of a long time recording mode to a compressed video signal, comprising: means for detecting the status information from the block, discriminating whether the recording mode is a standard recording mode or the long time recording mode, and setting a compression ratio in accordance with the standard recording mode or the long time recording mode; and video decompressing means for decompressing the video signal reproduced from the recording medium on the basis of the compression ratio.
According to the invention, there is provided a video apparatus comprising: decimating means which decimates a video signal of a predetermined unit at every predetermined interval and whose decimating interval can be changed; input means to which mode set inputs to set a standard recording mode and a long time recording mode are given; decimation changing means for varying the decimating interval in accordance with the mode set inputs from the input means; and recording means for forming blocks obtained by adding status information including information of the recording mode to the video signal and recording the video signal and the status information onto a recording medium on a block unit basis.
According to the invention, there is provided a video apparatus for reproducing a video signal and status information from a recording medium on a unit basis of a block obtained by adding the status information including information of a long time recording mode to the video signal, comprising: video interpolating means for detecting the status information from the block, discriminating whether the recording mode is a standard recording mode or the long time recording mode, and interpolating the video signal reproduced from the recording medium in accordance with the standard recording mode or the long time recording mode.
When the video signal is compressed and recorded onto the recording medium, by changing the compression ratio, the long time recording mode can be easily set. By dividing the video signal into the blocks of a fixed length and providing a header including information regarding the recording mode into the blocks, the recording and reproducing processes can be processed in a manner similar to the ordinary recording mode and the compression ratio can be easily set to a compression ratio according to the recording mode upon reproduction.
When the video signal is recorded onto the recording medium, by changing a subsampling interval, the long time recording mode can be easily set. By dividing the video signal into the blocks of a fixed length and providing a header including the information regarding the recording mode into the blocks, the recording and reproducing processes can be executed in a manner similar to those in the ordinary recording mode, and the interpolating process according to the recording mode can be easily performed upon reproduction.
The above and other objects and features of the present invention will become apparent from the following detailed description and the appended claims with reference to the accompanying drawings.